diff options
Diffstat (limited to 'kernel/debug/kdb')
| -rw-r--r-- | kernel/debug/kdb/kdb_io.c | 37 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_main.c | 1 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_private.h | 1 |
3 files changed, 13 insertions, 26 deletions
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index 98c9011eac78..e74be38245ad 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -30,6 +30,7 @@ char kdb_prompt_str[CMD_BUFLEN]; int kdb_trap_printk; +int kdb_printf_cpu = -1; static int kgdb_transition_check(char *buffer) { @@ -554,31 +555,26 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap) int linecount; int colcount; int logging, saved_loglevel = 0; - int saved_trap_printk; - int got_printf_lock = 0; int retlen = 0; int fnd, len; + int this_cpu, old_cpu; char *cp, *cp2, *cphold = NULL, replaced_byte = ' '; char *moreprompt = "more> "; struct console *c = console_drivers; - static DEFINE_SPINLOCK(kdb_printf_lock); unsigned long uninitialized_var(flags); - preempt_disable(); - saved_trap_printk = kdb_trap_printk; - kdb_trap_printk = 0; - /* Serialize kdb_printf if multiple cpus try to write at once. * But if any cpu goes recursive in kdb, just print the output, * even if it is interleaved with any other text. */ - if (!KDB_STATE(PRINTF_LOCK)) { - KDB_STATE_SET(PRINTF_LOCK); - spin_lock_irqsave(&kdb_printf_lock, flags); - got_printf_lock = 1; - atomic_inc(&kdb_event); - } else { - __acquire(kdb_printf_lock); + local_irq_save(flags); + this_cpu = smp_processor_id(); + for (;;) { + old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu); + if (old_cpu == -1 || old_cpu == this_cpu) + break; + + cpu_relax(); } diag = kdbgetintenv("LINES", &linecount); @@ -847,16 +843,9 @@ kdb_print_out: suspend_grep = 0; /* end of what may have been a recursive call */ if (logging) console_loglevel = saved_loglevel; - if (KDB_STATE(PRINTF_LOCK) && got_printf_lock) { - got_printf_lock = 0; - spin_unlock_irqrestore(&kdb_printf_lock, flags); - KDB_STATE_CLEAR(PRINTF_LOCK); - atomic_dec(&kdb_event); - } else { - __release(kdb_printf_lock); - } - kdb_trap_printk = saved_trap_printk; - preempt_enable(); + /* kdb_printf_cpu locked the code above. */ + smp_store_release(&kdb_printf_cpu, old_cpu); + local_irq_restore(flags); return retlen; } diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 2a20c0dfdafc..ca183919d302 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -60,7 +60,6 @@ int kdb_grep_trailing; * Kernel debugger state flags */ int kdb_flags; -atomic_t kdb_event; /* * kdb_lock protects updates to kdb_initial_cpu. Used to diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h index 75014d7f4568..fc224fbcf954 100644 --- a/kernel/debug/kdb/kdb_private.h +++ b/kernel/debug/kdb/kdb_private.h @@ -132,7 +132,6 @@ extern int kdb_state; #define KDB_STATE_PAGER 0x00000400 /* pager is available */ #define KDB_STATE_GO_SWITCH 0x00000800 /* go is switching * back to initial cpu */ -#define KDB_STATE_PRINTF_LOCK 0x00001000 /* Holds kdb_printf lock */ #define KDB_STATE_WAIT_IPI 0x00002000 /* Waiting for kdb_ipi() NMI */ #define KDB_STATE_RECURSE 0x00004000 /* Recursive entry to kdb */ #define KDB_STATE_IP_ADJUSTED 0x00008000 /* Restart IP has been |